Pressure accumulator of a hydraulic actuating system

ABSTRACT

A hydraulic actuating system is proposed in particular for gas exchange valves of reciprocating-piston internal combustion engines having a pressure source for the hydraulic medium and having at least one pressure accumulator, which can be connected to the pressure source; and has a piston which can be displaced in a drilled hole, a compression spring and a supporting element, for the compression spring with a central opening ( 3 ), which supporting element is fixed by a spring ring wherein the supporting element is configured as a spring supporting plate ( 1 ), the axial extension of which is considerably shorter than that of the piston.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national stage application filed pursuant to 35 U.S.C. 365(c) and 120 as a continuation of International Patent Application No. PCT/EP2011/061470 filed Jul. 7, 2011 and claiming priority from German Patent Application No. 10 2010 052 550.2 filed Nov. 25, 2010, which applications are incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The invention relates to a hydraulic actuating system that is configured, in particular, for gas exchange valves of reciprocating-piston internal combustion engines and that has a pressure source for the hydraulic medium and has at least one pressure accumulator, which can be connected to the pressure source, and said pressure accumulator has a piston that can be displaced in a drilled hole, a compression spring and a supporting element, which is fixed by means of a spring ring and is designed for the compression spring, with a central opening.

BACKGROUND OF THE INVENTION

A hydraulic actuating system of this type is known from the “MultiAir System” of the FIAT group, published under www.fiat.de/cgi-bin/pbrand.dll/fiat_Germany/news “Presse and Öffentlichkeitsarbeit [Press and Public Relations], January 2010”.

This system comprises a control block, which is mounted on a cylinder head of the reciprocating-piston internal combustion engine, has a pressure source for the hydraulic medium, contains a pressure accumulator and has an actuating device. The pressure accumulator has a piston, which is designed as a steel bushing. This piston is fed flexibly in a drilled hole in the control block, which is made of aluminum, and is pre-tensioned using a compression spring. The compression spring is braced by means of a supporting element also in the form of a steel bushing, which is identical to the piston, apart from an opening on the bottom side. This steel bushing brace is held by means of a round wire snap ring, which is supported by the drilled hole.

Due to the configuration and length of the steel bushing as the support, a considerable amount of material and work to create this is required. Since the only difference between the steel bushing as the piston and the steel bushing as the supporting element is the opening, further effort is required to ensure that the two parts are installed in such a way that they cannot be mixed up or this would result in the pressure accumulator malfunctioning.

BRIEF SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide a hydraulic actuating system comprising a pressure accumulator that can be easily manufactured and can be installed with no risk of confusing parts.

The invention achieves the above objective as the supporting element is configured as a spring brace plate, the axial extension of which is considerably shorter than that of the piston.

The spring supporting element can be made easily and inexpensively using the deep drawing process. The result is a cost effective supporting element that also cannot be mixed up with the piston, which is designed as the steel bushing, owing to the short design of the supporting element in terms of its axial extension.

The spring supporting plate exhibits, in essence, a constant wall thickness, has a flat bottom, a transition region, which is designed as a spherical shell, and a cylindrical ring; the outer shell of the ring acts as guidance into the drilled hole.

In this context, the opening in the bottom of the spring supporting plate can be punched out in addition to or at the same time as part of the deep drawing process.

BRIEF DESCRIPTION OF THE DRAWINGS

The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which:

FIG. 1 is a perspective view of a spring supporting plate; and,

FIG. 2 is a sectional view of the spring supporting plate.

DETAILED DESCRIPTION OF THE INVENTION

At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. While the present invention is described with respect to what is presently considered to be the preferred aspects, it is to be understood that the invention as claimed is not limited to the disclosed aspects.

Furthermore, it is understood that this invention is not limited to the particular methodology, materials and modifications described and, as such, may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described.

In FIGS. 1 and 2, a spring supporting plate is marked, to the extent that the details are shown, in general with reference number 1. The spring supporting plate (1), which has a constant wall thickness (see, in particular, FIG. 2) has a flat bottom (2) with a central opening (3). Connected on the outside to the flat bottom (2) is a transition region (4), which is designed as a spherical shell. Furthermore, a cylindrical ring (5) is connected to the transition region (4). The outer shell of the cylindrical ring acts as guidance into the drilled hole (not illustrated) and is adjusted to fit there. The spring supporting plate (1) is constructed in one piece. The spring supporting plate (1) is held in the drilled hole (not illustrated) by means of a spring ring, which is also not illustrated, or by means of a non-positive locking or positive locking connection.

Thus, it is seen that the objects of the present invention are efficiently obtained, although modifications and changes to the invention should be readily apparent to those having ordinary skill in the art, which modifications are intended to be within the spirit and scope of the invention as claimed. It also is understood that the foregoing description is illustrative of the present invention and should not be considered as limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention.

LIST OF REFERENCE NUMBERS

-   1 Spring supporting plate -   2 Bottom -   3 Opening -   4 Transition region -   5 Ring 

What is claimed is:
 1. A hydraulic actuating system configured for gas exchange valves of reciprocating-piston internal combustion engines that has a pressure source for the hydraulic medium, at least one pressure accumulator, which can be connected to said pressure source, and said pressure accumulator has a piston that can be displaced in a drilled hole, a compression spring, and a support element, which is fixed by means of a spring ring and is designed for the compression spring, with a central opening (3), wherein said support element further comprises: a design substantially similar to a spring supporting plate (1); and, an axial extension of said spring supporting plate (1) which is considerably shorter than that of said piston.
 2. The hydraulic actuating system recited in claim 1, wherein said spring supporting plate (1) is made using a deep drawing process.
 3. The hydraulic actuating system recited in claim 1, wherein said spring supporting plate (1) exhibits an essentially constant wall thickness with a flat bottom (2), a transition region (4), which is designed as a spherical shell, and a cylindrical ring (5), whereby an outer shell of said ring (5) acts as guidance into said drilled hole.
 4. The hydraulic actuating system recited in claim 1, wherein said opening (3) is manufactured using punching. 